IT systems are discussed generally and in particular in connection with a powered roadway application in international patent publication WO 2011/016736. In the system described in that publication, a pad to pad IPT transmission method is used. The pads include ferrite in both the transmitter and receiver pad in order to keep the size of those devices as small as possible whilst still transferring the required power. Specific construction of appropriate pads for an IPT roadway application is described in international patent publication WO 2010/090539 which includes an IPT magnetic flux transmitter or receiver, which is referred to in that document (and will also be referred to in this document) as a Double D pad design. The Double D pad design has excellent performance, and the pad arrangements constructed according to the design can be made less than 25-30 mm thick so that the receiving pad takes up very little space under the vehicle. Similarly, a transmitter pad according to the Double D design can be made sufficiently thin that it can be placed on or in the floor of a garage, for example for charging purposes.
The Double D pad design and other pad structures, typically use ferrite in order to produce the required flux. Ferrite has disadvantages of being brittle and expensive. In particular, in a vehicle and roading environment, ferrite is easily damaged. There is a need for developing an IPT flux transmission and/or reception apparatus which can tolerate vehicles such as 40-50 tonne trucks driving over them continually when placed in a roadway environment.
Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.